DECS-200 General Information 1-1
SECTION 1 • GENERAL INFORMATION
INTRODUCTION
The Basler Digital Excitation Control System (DECS-200) is a microprocessor-based control device
intended for generator power management. Programmability of system parameters and regulation
settings enables the DECS-200 to be used in a wide range of applications and provides greater flexibility
in excitation system optimization. The DECS-200 can accommodate generator exciter field requirements
up to 15 Adc continuously in 32, 63 or 125 Vdc applications with one model.
FEATURES
DECS-200 units have the following features and capabilities.
Functions
• Four control modes
o Automatic voltage regulation (AVR)
o Manual or field current regulation (FCR)
o Power factor (PF)
o Reactive power (var)
• Soft start buildup with an adjustable ramp in AVR and FCR control modes
• One adjustment range or pre-position setpoint for each control mode
• Overexcitation limiting (OEL) and underexcitation limiting (UEL) in AVR, var and PF control modes
• Twenty stability selections
• Underfrequency compensation or volts per hertz ratio limiter
• Autotracking between operating modes and between DECS-200 units (optional)
• Automatic transfer to a backup DECS-200 unit (optional)
• Eight generator protection features
o Field overvoltage
o Field overcurrent
o Generator overvoltage
o Generator undervoltage
o Watchdog timer
o Loss of sensing
o Exciter diode monitor (EDM)
o Loss of field
• Generator paralleling with reactive droop compensation and reactive differential compensation
• Data logging and event recording
Inputs and Outputs
• Single-phase rms bus voltage sensing
• Single-phase or three-phase rms generator voltage sensing
• Single-phase generator current sensing (1 or 5 amperes, nominal)
• Analog inputs (±10 Vdc and 4 to 20 mAdc) provide proportional, remote control of the setpoint
• Eleven PLC-compatible contact sensing inputs for system interface
• Separate ac and dc power inputs accommodate redundant operating power sources
• Pulse-width modulated output power stage rated at a maximum of 15 amperes, continuous
• Five output relays for system control or annunciation
o Three programmable output relays
o Two fixed-function output relays
HMI Interface
• Front panel HMI includes pushbutton controls, LED indicators and a backlit, liquid crystal display
(LCD)
• BESTCOMS Windows® based software provides easy, fast and accurate setup and control